I am running a intank TBI fuel pump right now. It is about 2.5 years old. I swapped to carb about 1.5 years ago. I am running a 3 port return style mallory fuel pressure regulator. I recently got around to installing a real fuel pressure gauge...not a cheap POS from autozone.

I was running way to much so I turned it down to 5psi. Next day I go out to check and its at 2psi. Turn it up...it will be at 10psi the next day. This keeps happening.

Is it possible the TBI pump is finally dieing? I have a holley blue fuel pump I am about ready to install. Think this will help anything?

 

sounds more like a regulator problem

 

I also have a holley regulator that came with my holley blue pump. I had planned on using that for my nitrous soleniod but I may not be able to.

For a 100 shot of nitrous do you think I could just use the holley reg...run the fuel line in and run one line to the carb and one line to the fuel soleniod? Its a holley blue so it should be able to supply enough fuel that way.

 

Ok I got a few pictures...I do not see how the regulator could be messed up. It is too simple.

I had my fuel return line on the bottom port and the inlet/outlet on 2 of the other ports around the top.

Now that I look at it it appears that the fuel should be coming in the bottom...I don't see how it regulates if its connected to the side ports.....

 

Here is the inside piece....

Shouldn't the fuel pressure be coming in from the bottom and forcing the cone upward? Which would create tension on the sprigs....so screw the reg down should inturn cut fuel off correct....

 

No, fuel supply should defintiely be coming in the side and the line to the carb should also be coming out the side as well. Bypass goes on the bottom.

The bypass opens by the pressure inside the main body of the unit pushing up on the diaphragm and lifting the needle valve off it's seat to bypass excess pressure back to the tank.

There's another post similar to this in the Carb section you may want to check out.

 

Damon is exactly right, you might have had it backwards on the hookup.

I have fluctuations in pressure with my setup (which is exactly the same as yours), but not more than .5 PSI.

 

I had it hooked up right. Return line was on the bottom and the inlet/outlet were on the sides.

I still think my fuel pump could be going bad. I am getting ready to go buy some fuel line so I can hook the holley reg up and see what happens.

 

if you are running a TBI pump that pushes alot more psi than what your carb needs and you are using a pressure regulator on it to keep the psi's down, then your pump could be burning up. I've heard of that before once or twice.